Start work on keystone auth backend proper

Just rigs up the wsgi wrapper and loads the config; still WIP.

haas/ext/auth/keystone.py

@@ -0,0 +1,22 @@
+from keystonemiddleware.auth_token import filter_factory
+from haas.flaskapp import app
+from haas.config import cfg
+import logging
+import sys
+
+logger = logging.getLogger(__name__)
+
+
+def setup(*args, **kwargs):
+    if not cfg.has_section(__name__):
+        logger.error('No section for [%s] in haas.cfg; authentication will '
+                     'not work without this. Please add this section and try '
+                     'again.' % __name__)
+        sys.exit(1)
+    keystone_cfg = {}
+    for key in cfg.options(__name__):
+        keystone_cfg[key] = cfg.get(__name__, key)
+
+    # Great job with the API design Openstack! </sarcasm>
+    factory = filter_factory(keystone_cfg)
+    app.wsgi_app = factory(app.wsgi_app)